Filtration Technology Study Of Biological Filter Of The New Type Of AC Media

A new type of filtration is developed to remove not only suspended matters but also more organic pollutants than traditional filter due to the contamination of source water in our nation recently. It is named biological filter of the new type of AC media, which is the filter bed made up of single-layer media AC or dual-layer AC-anthracite media.The model experiments about filtration were done to treat the micro-organic-polluted raw water of Tuo-river in Neijiang city. 173 kinds of organics were examined from the Tuo-river raw water, and the sand harmonious bed of 1.2m depth was just found out to remove 7.85% COD_Mn and 44.05% NH₃-N averagely. Study indicated that at the filtration rate of 6m/h, as filled with air(air-water ratio of 1:1), the bilayer media filter made up of AC and anthracite removed 21.3% COD_Mn and 61% NH₃-N averagely, and the AC media filter removed 15.9% COD_Mn and 57% NH₃-N averagely. Two filters could produce water whose quality meets the national drinking water quality standard.A method by adding aeration system was put forward to change a traditional V type filter with yields of 100,000m³/d made up of sand harmonious bed to biological filter made up of AC and anthracite filter media. It could be concluded that dual-layer AC-anthracite biological filter was more economical than the dual-layer GAC-sand biological filter and ozone-GAC filter according to the integrated analysis of project invest, running cost, unit making cost and energy consumption of four filters. In this paper, several problems were studied and discussed about the AC media filter including the essential performances of the filter, the mechanisms of organic matters removal and oxygen transport in water and the way of aeration. In addition, the mathematical models of the initial head loss, the turbidity removal and organic matters degradation were established.The fruits of the study are suitable for water plants on a middle or small scale to strengthen the function of removal of organic matters from micro-organic-polluted raw water of traditional filters.